Early diagnosis of pancreatic cancer is important for increasing survival from this rapidly fatal disease. Promising immunossays for detection of pancreatic cancer recognize pancreatic cancer- associated mucins in serum. A monoclonal antibody that compares favorably in sensitivity and specificity to the available immunoassays, 19-9 and DU-PAN-2, has recently been developed in this laboratory. The pancreatic cancer mucin recognized by this antibody has also been purified from xenografts of the SW- 1990 pancreatic cancer cell line and characterized to a considerable extent. We propose to use the purified mucin to generate antibodies with increased specificity for different components of the mucin molecule and to further characterize the antibodies already produced. We also plan to isolate and characterize, by mass spectrometry, purified oligosaccharides from pancreatic mucin. Since little is known about the polypeptide sequence of pancreatic or other mucins, the purified mucin will be deglycosylated and used to obtain protein-specific antibodies and partial peptide sequences. This will be used to identify cDNA for pancreatic mucin, which should allow complete characterization of the mucin protein. Because the mechanisms that result in the appearance of pancreatic cancer mucin in serum are poorly understood, the biosynthesis, processing, and secretion of mucin in cultured pancreatic cancer cells will be investigated using metabolic labeling, mucin-specific antibodies, and cDNA probes. The availability of a cultured cell system, of a panel of mucin-specific antibodies, and of a continued source of purified mucin gives the opportunity to elucidate the immunochemistry, structure and molecular biology of pancreatic cancer mucin. These studies should prove useful in increasing our understanding of the biochemistry of pancreatic cancer cells and especially in improving the available diagnostic tools for detection of pancreatic cancer.